Designing My Soffit Mounts

Start your own studio thread here: Goals, plans, layouts, treatment, speakers, questions, queries, comments...
User avatar
snailboyawayyy
Active Member
Posts: 30
Joined: Thu, 2020-Jun-11, 11:53
Location: London, UK

Designing My Soffit Mounts

#46

Postby snailboyawayyy » Wed, 2021-Jun-09, 10:28

So I thought some more about it & I think its fine?

I realized that the graph I linked above compares double-leaf & triple-leaf systems that use the same overall thickness & mass.

They're essentially doing the tests with the same number of drywall sheets & wall space. like so:
Image
So it makes sense that the triple-leaf system would perform poorly in the lower frequencies, because the resonance frequencies of the air gaps have increased because they're smaller. The larger the air-gap, the lower the resonance frequency.

(Would recommend reading Stuart's thread on MSM (double-leaf) systems in walls, if you haven't already. It explains all of this v well: https://www.digistar.cl/Forum/viewtopic.php?t=413)

MY situation differs in that I'm not sacrificing any amount of spring gap (my spring being rubber instead of air) for the sake of making it triple-leaf. The gap inside the speaker box is unchanged.
The wall equivalent would be keeping the original, large air gap & adding another air gap+drywall combo on one side. The resonance frequency would stay the same because the original air-gap hasn't been changed and the isolation above the resonance frequency would be improved by the new 'layer' (of course, you might not want to do this as you're spending more money on materials & sacrificing room space for a thicker wall).
THAT SAID, in a wall situation it would still be better to use that space for one large air-gap, as you can drive the resonance frequency even lower & get much better isolation of the bass frequencies.

But in my case I can't make my Sorbothane any thicker than 1", so my best option IS to go triple-leaf.

One thing that DOES carry over to my situation is that by separating the housing box from the overall soffit structure I'm effectively 'splitting the mass', which can result in a higher resonance frequency. However the weight of the housing box pales in comparison to the weight of the entire soffit structure so really I'd only be splitting the mass a little bit. Theoretically the benefits should massively outweigh this very slight pitfall.

What should result from my triple-leaf system is a low-end performance roughly equal to that of a double-leaf system, but a much better performance in the mids & highs. Sort of like this:
h.jpg



User avatar
snailboyawayyy
Active Member
Posts: 30
Joined: Thu, 2020-Jun-11, 11:53
Location: London, UK

Designing My Soffit Mounts

#47

Postby snailboyawayyy » Wed, 2021-Jun-09, 10:38

I feel more often than not with these things that simple is better. I wonder by having so many layers/leaves each floated using Sorbothane is making things complicated in a way that could be detrimental. Maybe start with a design like mine and see how you get on? If that isn’t as good as hoped, taking off the baffle to add additional Sorbothane damping/isolation won’t be that difficult? Better to start with solid framing and see how you get on, I wonder?

I won't lie I was right on the cusp of abandoning the triple-leaf system but then I realized I still needed 2 6x6 sheets (Gelmec only sell 1" sheets in 6x6 and 12x12 and i need around one and a quarter sheets of 6x6 for the inside of the housing boxes). I could've cancelled the washers but I figured I may as well try & make sense of the triple-leaf pitfalls and I could always sell the washers if I decide too late.
Feeling a lot more confident about the triple-leaf system now :D

I should imagine there will be other elements of the room/design that have a greater impact on the sound than this?
You are almost certainly correct about that lol




  • Similar Topics
    Statistics
    Last post

Who is online

Users browsing this forum: No registered users and 11 guests